JPH077554Y2 - Exhaust gas temperature reduction device - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas temperature reducing device having a function of reducing the temperature of high temperature exhaust gas discharged from an exhaust pipe of a ship or a vehicle.

[0002]

2. Description of the Related Art In particular, when a gas turbine engine is used, the exhaust gas has a very high temperature (500 ° C. or higher). Such exhaust gas is discharged from the chimney (exhaust pipe) in ships, etc., but when electronic devices such as radar are installed around the chimney, the electronic devices are thermally affected by the exhaust gas and operate normally. Doing so may cause failure. Further, the hot exhaust gas also has a problem in that it emits a large amount of infrared rays.

Therefore, conventionally, a short pipe having a diameter slightly larger than that of the exhaust pipe is continuously provided at the outlet end of the exhaust pipe with a constant gap around the outlet pipe, and cooling air is supplied from this gap to the inner peripheral wall of the short pipe. A device (Japanese Utility Model Publication No. 63-19540) is proposed in which the contact between the high-temperature exhaust gas and the inner peripheral wall of the short pipe is cut off by flowing the gas along the pipe to prevent the temperature rise at the outlet of the exhaust pipe.

[0004]

However, the apparatus described in the above publication has room for improvement in the following points. That is, since the short pipe, which is the outlet portion through which the exhaust gas is discharged, is cooled by the cooling air, the temperature rise can be avoided, but the exhaust gas itself is hardly cooled. As a result, high-temperature exhaust gas is discharged, and the exhaust gas may adversely affect the electronic device thermally or emit a large amount of infrared rays.

The present invention has been made in view of the above-mentioned point, and the high temperature gas and the outside air can be evenly and uniformly mixed with the shortest distance and the smallest pressure loss, and the temperature can be reduced as a whole. The purpose is to provide a device.

[0006]

Exhaust gas temperature reduction apparatus of this invention in order to achieve the above-mentioned object, according order to achieve the above, the mixing tube having a flare gradually enlarged diameter toward the a) upstream the upstream end An exhaust gas temperature reducing device extending downstream from the vicinity of the exhaust gas exhaust pipe outlet end, b) into the peripheral wall of the exhaust pipe outlet portion recessed toward the center and upstream from the outlet end Folded outside air guide grooves are formed at intervals in the circumferential direction so that the degree of the concave shape gradually decreases toward the side.

Further, as described in claim 2, c) the concave depth and the groove length of each of the outside air guiding grooves are alternately set.
It is preferable to make it deep and long and shallow and short.

Further, as described in claim 3, d) each of the outside air guiding grooves may be spirally formed in the same direction from the upstream side to the downstream side.

[0009]

According to the exhaust gas temperature reducing device of the present invention having the above-mentioned structure, the high-temperature exhaust gas passes through the exhaust pipe at a relatively high speed, and goes from the outlet of the exhaust pipe toward the upstream mixing pipe. Flowing. This high-temperature exhaust gas flow causes a kind of suction force to guide the outside air along each outside air guide groove around the outlet of the exhaust pipe, and together with the exhaust gas flowing out from the outlet of the exhaust pipe, the downstream side of the mixing pipe. A large amount of outside air is sucked into the mixing pipe through the gap between the flare and the outlet of the exhaust pipe. In this way, since the outside air is sucked into the mixing pipe from the surroundings by the exhaust gas flow, no equipment such as a fan and its driving device is required.

Further, each of the outside air guide grooves enters a concave shape from the outer periphery of the exhaust pipe toward the center, and the exhaust air discharged from the exhaust pipe is almost evenly outside air from the peripheral portion of the outlet of the exhaust pipe to the central portion. While being mixed and passing through the mixing pipe, the exhaust gas and the outside air are uniformly mixed as a whole. Therefore, the temperature of exhaust gas discharged from the outlet of the mixing pipe is reduced substantially uniformly and the mixing efficiency is good, so that the mixing distance is short. Furthermore, since the outlet of the exhaust pipe is gradually narrowed toward the outlet by a plurality of outside air guide grooves,
The flow velocity of the exhaust gas gradually increases toward the outlet, enhancing the action of sucking outside air. When the outlet of the exhaust pipe is squeezed into a simple conical shape toward the downstream side, the temperature distribution of the exhaust gas discharged from the outlet of the mixing pipe becomes mountain-shaped and the temperature rises at the center. According to the devised device, it is almost uniform overall.

Particularly, in the exhaust gas temperature reducing device according to the second aspect, the degree of entering the concave shape from the outer circumference of the exhaust pipe toward the center is alternately shallow and deep, and the length of the groove is alternately short and long. As a result, the exhaust gas exhausted from the exhaust pipe is evenly mixed with the outside air from the periphery of the outlet of the exhaust pipe to the center, and while passing through the inside of the mixing pipe, the exhaust gas and the outside air are surely uniform throughout. Mixed in.

According to the exhaust gas temperature reducing device of the third aspect, the outside air flows into the mixing pipe so as to be twisted spirally along each of the outside air guiding grooves, and becomes a swirling flow in the mixing pipe. On the other hand, the outside air is mixed more efficiently.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of an exhaust gas temperature reducing device of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially omitted perspective view showing an exhaust gas temperature reducing device according to an embodiment of the present invention. As shown in the figure, the exhaust pipe 1 is composed of an exhaust pipe body 4 and an exhaust nozzle 2, and a flange 2 a is provided around the lower end of the exhaust nozzle 2.
Is integrally provided and is connected to a flange 4a provided around the upper end of the exhaust pipe main body 4 by a plurality of bolts and nuts.

A fold-shaped outside air guide groove 3 is formed in the circumferential wall of the exhaust nozzle 2 from the outlet end downward to the center from the outer circumference, and the degree of the concave entry gradually decreases downward. It is formed at equal intervals. Further, the outside air guiding grooves 3 are alternately set to have a concave depth and a length 3a that are deep and long and a depth 3b that is shallow and short.

A mixing pipe 5 having a diameter slightly larger than that of the nozzle 2 is provided immediately above the exhaust nozzle 2. A flare 6 whose diameter is gradually increased downward is integrally attached to the lower end of the mixing tube 5.

FIG. 2A is a view taken along the line AA of FIG.
2B is a sectional view taken along the line BB of FIG. As shown in these figures, in this embodiment, eight outside air guiding grooves 3 are formed at equal intervals in the circumferential direction, and the concave depth is deep and the groove length is long, and the concave depth is 3a. Shallow and short groove lengths 3b face each other and are alternately arranged.
Although the dimensions and the like are not limited, when the nozzle 2 has a diameter of 386 mm and a length of 550 mm, the depth of penetration of the outside air guiding groove 3a toward the center is 16
The groove length is set to 0 mm, the groove length is set to 437 mm, and the inclination α'is set to 25 °. The depth of entry of the outside air guiding groove 3b toward the center is 77 mm, the groove length is 217 mm, and the inclination α is set to 20 °. . Thus, the width of each groove 3a and 3b is set to 38
mm, and the opening cross section of the outlet end of the exhaust nozzle 2 was narrowed to 70% of the opening cross section of the portion where the outside air guide groove 3 was not provided.

In the exhaust pipe 1 having the above-mentioned exhaust nozzle 2, the exhaust gas a at 500 ° C. is discharged into the upper mixing pipe 5 through the exhaust nozzle 2 as shown in FIG.
The mixing distance L of the exhaust gas discharged from the outlet of the
(D: diameter of exhaust pipe 1) was set and the temperature distribution of exhaust gas at the same distance was measured. At this time, the flow rate of the exhaust gas a was 300 m ³ / min, and the flow rate was 43 m / sec. As a result of the experiment, an even temperature distribution of about 390 ° C. and a maximum temperature of about 415 ° C. was obtained. Further, when the exhaust gas a is discharged from the exhaust nozzle 2, the outside air b is guided along each of the outside air guide grooves 3 around the exhaust nozzle 2, and a large amount of the outside air is discharged together with the exhaust gas a at the lower end of the mixing pipe 5. It was confirmed that the flare 6 was sucked into the mixing tube 5 through a gap between the flare 6 and the outlet of the exhaust nozzle 2.

On the other hand, in order to compare with the exhaust nozzle 2 of the present invention, although not shown, a device in which the outlet portion of the exhaust pipe is conically narrowed to an opening ratio of 70% was manufactured and tested under the same conditions as above. However, the temperature distribution of the exhaust gas discharged from the mixing pipe 5 has a mountain shape, and the maximum temperature at the center is 49
Almost no decrease in temperature of 7 ° C was observed.

FIG. 4 is a perspective view showing an exhaust nozzle according to another embodiment of the present invention. The exhaust nozzle 12 of the present embodiment is different from the exhaust nozzle 2 of the above embodiment in that each of the outside air guide grooves 13 is formed by spirally inclining in the same direction from the lower end to the upper end. For this reason,
The outside air around the nozzle 12 is guided along the spiral outside air guide groove 13 into the mixing pipe 5 (FIG. 1) while being guided, thereby forming a swirling flow in the mixing pipe 5 and efficiently mixing with the exhaust gas. It

In each of the above embodiments, the exhaust nozzle 2 or 12 is connected to the exhaust pipe body 4 (FIG. 1), but the exhaust nozzle 2 or 12 and the exhaust pipe body 4 are integrally formed. Good. In this case, the outlet of the exhaust pipe 1 corresponds to the exhaust nozzle 2 or 12. Further, although the exhaust pipe 1 and the mixing pipe 5 are arranged in the vertical direction, the present invention is not limited to this, and it goes without saying that the same can be done by arranging them in an oblique direction or a horizontal direction.

[0022]

[Effect of the Invention] As is clear from the above explanation,
The exhaust gas temperature reduction device of the present invention has the following effects.

(1) Since the outside air is uniformly mixed with the high temperature gas discharged from the outlet of the exhaust pipe, the temperature of the high temperature gas can be reduced uniformly throughout, and a large amount of outside air is introduced into the mixing pipe. Since it is mixed with the high temperature gas, the mixing distance required for uniform mixing can be short. In particular, since the mixing distance becomes short, the height of the chimney can be reduced in a ship. Further, in the conventional device described in the above publication, the vicinity of the inner peripheral wall of the short pipe connected to the upper end of the exhaust pipe is cooled by the outside air to suppress the temperature rise at the exhaust pipe outlet, whereas the device of the present invention. Since the temperature of the high temperature gas itself is reduced, not only the vicinity of the outlet of the exhaust pipe but also the thermal influence of the gas after discharge is reduced, and the infrared radiation from the gas is also reduced.

In addition, the structure of the device is simple and the device can be made compact, so that the device can be easily mounted on a ship or a vehicle.

(2) In the exhaust gas temperature reduction device according to the second aspect, the exhaust gas exhausted from the exhaust pipe is uniformly mixed with the outside air from the peripheral portion of the outlet of the exhaust pipe to the central portion and passes through the inside of the mixing pipe. During this, the exhaust gas and the outside air are surely mixed uniformly throughout.

(3) In the exhaust gas temperature reduction device according to the third aspect, the outside air is introduced into the mixing pipe so as to be twisted spirally along each of the outside air guiding grooves and becomes a swirling flow in the mixing pipe.
The outside air is more efficiently mixed with the exhaust gas.

[Brief description of drawings]

FIG. 1 is a partially omitted perspective view showing an exhaust gas temperature reduction device according to an embodiment of the present invention.

2A is a view taken along the line AA of FIG. 1, and FIG. 2B is a sectional view taken along the line BB of FIG. 2A.

FIG. 3 is a perspective view, partly omitted, schematically showing a usage state of an exhaust gas temperature reduction device.

FIG. 4 is a perspective view showing an exhaust nozzle according to another embodiment of the present invention.

[Explanation of symbols]

 1 Exhaust pipe 2/12 Exhaust nozzle 3.3a / 3b / 13 Outside air guide groove 4 Exhaust pipe body 5 Mixing pipe 6 Flare

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshimasa Sakai 3-1-1 Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries, Ltd. Kobe factory (56) References: 60-28231 JP, U ) Actual development Sho 63-143721 (JP, U)

Claims (3)

[Scope of utility model registration request] 1. A mixing tube with the upstream end of the flare gradually enlarged diameter toward the upstream side, formed by extending downstream from the vicinity of the outlet end of the exhaust pipe of the exhaust gas exhaust gas temperature reduction apparatus In the peripheral wall of the outlet portion of the exhaust pipe, fold-shaped outside air guide grooves are formed at intervals in the circumferential direction, which are recessed toward the center and gradually decrease in degree from the outlet end toward the upstream side. An exhaust gas temperature reduction device characterized in that 2. The exhaust gas temperature reduction device according to claim 1, wherein the depth of depression and the groove length of each of the outside air guiding grooves are alternately deep and long and shallow and short. 3. Each of the outside air guiding grooves is arranged from the upstream side to the bottom side.
The exhaust gas temperature reduction device according to claim 1 or 2, wherein the exhaust gas temperature reduction device is formed spirally in the same direction toward the flow side.